High-frequency corn popping apparatus



March 25, 1952 E. L. SCHIAVONE 2,590,580

- HIGH-FREQUENCY CORN POPPING APPARATUS Filed July 26, 1946 4 Sheets-Sheet 1 I8 OSCILLATOR POPPING- TIME CONTROL (mum g 63 0\,: 65

E. 1.. SCHIAVONE HIGH-FREQUENCY CORN POPPING APPARATUS March 25, 1952 Filed July 26, 1946 4 Sheets-Sheet 2 EdWar/ZZLJckz'a mze lllllll'llll & m g h an I i:

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EdWakdL. xS ckz'aVone Patented Mar. 25, 1952 HIGH-FREQUENCY CORN POPPING APPARATUS Edward L. Schiavone, Silver Spring, Md., assignor of one-half to Ben J. Chromy, Washington,

Application July26, 1946, Serial No. 686,488

12 Claims. 1

This invention relates to dispensing, vending and heating apparatus ingeneral. More particularly, this invention relates to check and/or time controlled high frequency electrical heatin devices for vending or dispensing apparatus.

An object of this invention is to provide an arrangement for popping corn through the use of radio frequency currents.

Another object of this invention is to provide an apparatus employing electrode means in the nature of capacitor electrodes which are energized or charged by high frequency electric current and between which'are supported kernels of popcorn for the popping thereof.

Another object of this invention is to provide a check and time control for high frequency electrical heating apparatus.

Another object of this invention is to provide a high frequency electrical heating apparatus for vending and/or dispensing machines of the type vending and/or dispensing-edible products that it is desirable to heat prior to consumption.

A further object of this invention is to provide an electrical heating apparatus control for a vending or dispensing machine 'of a type adapted to vend or dispense an edible product such as popcorn immediately after it ispopped or heated in a sealed package.

Still another object of this invention is to provide a dispensing or vending apparatus for re- K ceiving a plurality of scaled packages of edible products such as popcorn and for vending or dispensing such products in the original sealed package.

Still a further object of this invention relates to a control circuit for electrically heating and dispensing edible products in the original packages while hot without opening and rescaling the original packages or damaging such packages.

A still further object of this invention is to provide an electrical heating and dispensing apparatus for heating and dispensing edible products such as popcorn in individual packages without the necessity of opening and rescaling such packages once they have been placed in the heating and dispensing apparatus.

Another object of this invention is to provide an electrical apparatus for popping corn packaged in individual packages and dispensing the corn in such packages immediately after it is popped.

Other and further objects of this invention will be apparent to those skilled in the art to which this invention relates from the following specification and the claims.

I have found that high frequency electric our-- rents may be efficiently employed in the popping of corn primarily because the greatest heatin action produced by the high frequency currents is concentrated in the interior of the popcorn kernel. In other words, the interior of the corn kernel becomes heated and the water vapor therein causes the kernel to explode without the skin of the kernel being impaired by heatin action prior to the popping of the kernel. Furthermore, employing high frequency current for popping corn increases the efficiency and rapidity with which the corn is popped because of this concentrated heating action. In accordance with this invention, I have provided a high frequency capacitor electrode arrangement between which the kernels of popcorn are supported preferably in a single layer. erator is connected to these capacitor electrodes and this supplies the high frequency current for heating the popcorn kernels. The heating action in the popcorn kernels is in the nature of a dielectric loss which takes place in the kernel inasmuch as the kernel is in the nature of a dielectric and this loss is proportional to the dielectric constant of the inside of the popcorn kernel and the frequency of the high frequency oscillations supplied to the capacitor electrodes. Consequently by varying or controlling the frequency of the high frequency oscillation generator the time required for popping the corn may be controlled, that is, the time may in general be reduced by increasing the frequency of the high frequency oscillations. Furthermore, the corn kernels may be impregnated with a suitable oil or other liquid if it is desired to increase the dielectric constant of the interior of the corn kernel. This would of course also cause the corn kernels to pop faster since the dielectric losses therein would be increased thereby.

Other features of this invention will be set forth in detail in the following specification, claims and the drawings.

Referring to the drawings briefly:

Fig. 1 is a view showing structural details and a schematic wiring diagram of the electrical circuit employed in my invention; Fig. 2 is a schematic wiring diagram of the high frequency current generator adapted to be employed in my invention; Fig. 3 is a detail view of the motor control relay employed in this invention; Figs. 3a. and 3b are detail views of the leverage employed to trip the mercury switch of the motor control relay shown in Fig. 3; Fig. 4 is a vertical sectional view of the coin trip mechanism and electromagnetic interlock employed therewith in ac- A high frequency oscillation gen- 25 of insulation or other suitable material.

. 3 cordance with this invention; Fig. 5 is a sectional view taken along the line 5-5 of Fig. 4; Fig. 6 is a sectional view taken along the line 6-6 of Fig. 4; Fig. '7 is an end view of the motor driven conveyor employed in this invention; Fig. 7a is a fragmentary side view of one of the conveyor supporting and actuating drumsjFig. 7b is a plan view of the conveyor, top electrode structure and popcorn bag bin; Fig. 8 is a detail view of a thermal switch employed in a modified form of this invention; and Fig. 9 is a detail view of the high frequency electrodes with a bag of popped popcorn therebetween, and the contactor associated with the top electrode; and Fig. 10 is a view of the cabinet partially cutaway to show mounting of some of the apparatus inside.

Referring to the drawing in detail, reference numeral ll designates a plug of conventional design adapted to be inserted into a conventional wall receptacle connected to a 110 volt alternating current lighting or power circuit. A pair of conductors i4 and I5 are attached to the conductors I2 and I3, respectively, and these former conductors are connected to terminals I6 and I7, respectively, of the high frequency current generator H5, The terminals 5 and H are connected to the primary of the high frequency generator filament or cathode power transformer, as will be more particularly set forth, so that when the plug i0 is connected to a supply of 110 volt alternating current and the switch I! is closed the power transformer of the generator I8 is energized and the filaments of the generator tubes are heated to electron emissive temperature.

The conductor |2 is also connected to the contact l9 of the contactor K, supported by the arm The other contact 2i) of the contactor K is supported by an isulation element a, as is illustrated in the vertical sectional view shown in Fig. 3, and is connected through the conductor 26 to the terminal 2? of the high-frequency-generator-platecircuit controller D. The other terminal 28 of the winding of the controller D is connected through the conductor 29 to the terminal 30 of the winding C of the ooin-closed-circuit interlock and the other terminal 3| of this winding C is connected-to the contact 32 of this interlock circuit. The contact 32 is supported by insulation attached to the coin slot, as will be described in connection with Figs. 4 and 5. The contact 33 of the interlock circuit is connected to the 110 volt circuit conductor it through the wire 34.

Furthermore, the wire I2 is also connected to the terminal 2| of the winding 1, the other terminal 22 of this winding I being connected through the conductor 35 to the contact 36 of the contactor H. The other contact 3! of this contactor H is connected to the conductor 38 and thence to the conductor l3. The details of construction of the contactor H are illustrated in Fig. 9, and they are described in the description of this figure.

Still further, the wire I2 is connected to the terminal 23 of the mercury switch J, the terminal 2 1 of this switch is connected to the terminal 40 of the motor 39 and the other terminal 4| of the motor is connected to the conductor l3. The details of construction and mounting of the mercury switch and associated devices are illustrated in Figs. 3, 3a and 3b. The wire |2 is connected to one side of the 110 volt A. C. plug l0 through the switch H and the other side of this plug I5 is connected to one side of the winding 50 of the electromagnetic shutter arrangement. This electromagnetic shutter arrangement is provided with an armature 5| associated with the winding 50 and mechanically connected to a coin diverting member or scoop 52 which reaches into the coin receiving chute of this apparatus and diverts the coins from the coin slot when the circuit of the apparatus is not at least partially energized, for example, when the switch I is open or when the plug I0 is not inserted into the current carrying receptacle. This will be described in detail in the operation of the apparatus.

Referring to Fig. 2 in detail, the primary winding of the transformer 60 is connected to the terminals l6 and I! which correspond to the terminals l6 and ll of Fig. 1, and which are connected to the lines l2 and I3 adapted to be associated with a volt lighting circuit or similar power circuit. The secondary of the transformer 60 is connected to the cathodes of the electric discharge devices 6! and 62. Each of these devices is provided with a cathode, a grid electrode and an anode, the grid electrode being positioned between the cathode and the anode. The cathodes of the electric discharge devices 5| and 62 are permanently connected to the secondary of the transformer 60 and these cathodes are heated to electron emissive temperature when the plug H! is operatively associated with a suitable power line and the switch is closed. A second transformer 63 having a primary winding and a secondary winding is employed for energizing the anodes of the devices 6| and 62 and the primary of this transformer 53 is also connected to the terminals l6 and I? to be energized from the lines [2 and I3; however, in this case this transformer is not energized immediately upon the closing of the switch II, but its operation is dependent upon the closing of the contacts E of the relay D, these contacts E being connected across the terminals 64 and 65, as shown in Fig. 1, said terminals corresponding to like designated terminals in Fig. 2. When the contacts E of relay D are closed and the transformer 63 is energized, a relatively high voltage is applied alternately from the halves of the secondary of'this transformer across the anode-cathode discharge space of the devices 6| and162. Theanodes of the devices 6| and 62 are coupled through condensers Stand 61, respectively, to a terminal of'an. oscillatory or tank circuit 68, The other terminal of this tank circuit is coupled through condenser ID to the grids of the dischargedevices 6| and 62. The grids of these discharge devicesfi and 62 are connected together through a suitable potentiometer for balancing purposes, and the variable contact of this potentiometer is connected to the condenser iii and to the grid resistor 10a, which functions as a suitable conductive circuit back to the center tap of the filament transformer secondary. This center tap is bypassed for high frequency currents. to the outer treminals by. suitable condensers, and the common connection of these condensers is connected to the terminal 69 of the inductance of the tank circuit 68. High frequency currents are derived from the tank circuit 53 through suitable connection employing the coupling condensers H and 12 which are connected to the terminals 13 and 14, respectively. These terminals 73 and 14 are also shown on Fig. 1 whereterminal 13 is connected by the conductor i5'to the high frequency brush contactor Tl, shown in detail in Fig. 7a. Terminal M is connected by a conductor 16 to the high frequency electrode F, which is shown in detail in ,9 j Uj iii Referring to Figs. 3 and3a, these figures illustrate details of the e'lec'tromagnetically and mechanically controlled mercury switch -J "and the contactor K. The "mercury switch J is held on the member 86 by a metal strap 86a hugging portions of the top and sides of the casing of said switch. These casings are usually made of glass or similar insulation material however they may be made partially of metal and partially of insulation. If the casing is of metal a suitable insulation sleeve must be positioned between this metal and the strap 83a as well as between it and the metal of the member 86. The member 86 may of course be practically entirely of insulation material, such as Bakelite and a small metal, that is, iron, armature 86b attached to the bottom thereof so that the member 86 may be electromagnetically actuated by the solenoid I. This solenoid is provided with an iron core 860 around which the winding 86d of the solenoid is positioned and from which said winding is insulated. The core 86c is provided with a threaded hole for receiving the flat headed bolt 86c and fastening the solenoid assembly to the bottom of the housing 86f. The wires I2 and 35 leading to the winding of the solenoid I enter the housing 86f through suitable insulation bushings or sleeves 2Ia and 22a respectively. Likewise the wire 26 connected to the contact 20 passes through the insulation bushing 26a in a side wall of the housing 86] and the wire connected to the terminal 24 of the mercury switch J passes through the insulation bushing 24a into the housing. On the other hand the terminal 23 of the mercury switch J and the terminal 2I of the solenoid are connected to the contact I9 inside of the housing and therefore no bushings are required for these wires.

The member 85 supporting the mercury switch J and the contact I9 of the switch 'K, is pivoted at 93 and is rotatable through a limited angle about this point. The pivot 93 is supported by the housing 861 and supports the popcorn bag receiving-scoop-shaped member 92 on the ends thereof externally of the aforesaid housing as shown in the side view Fig. 3a and top view Fig. 3b.

In Figs. 4, 5 and 6 are illustrated details of construction of coin tripped electromagnetic switch arrangement, the contact 32 and 33 supporting members 32a and 33a of which are attached to the coin chute 80 by bolts 80b which are insulated from the members 32a and 33a by insulation spacers 80a. The members 32a and 33a are also insulated from each other except when the member 33a is depressed by a coin 9I so that the contacts 32 and 33 are in engagement. When the member 33a .is depressed by a coin 9I the armature 33b is positioned in the air gap between the pole faces of the core 330 of the magnetic device C as shown in dotted outline in Fig. 6. When this apparatus is in normal working order the member 33a is held in this depressed position shown in dotted outline in Fig. 6 until the bag of popcorn 84 in position under the high frequency electrode F expands to popped condition and the switch or contactor K is opened so that the winding C is de-energized as more fully described under the portion of this specification dealing with the operation of this apparatus.

Referring now to Figs. 7 and 7a wherein details of the conveyor 8| supporting drum 83 and some of the associated devices are shown, it will be observed that the high frequency current 00111 6 ducting brush 11, connected to the oscillator I3 by the wire 15, is urged by the spring 'IIa into frictional contact with the drum 83. The drum 83 is a metallic .tube supported in the bearings 83g and 83d by the shaft83b and the spokes 83a, the latter being preferably of insulation material so that high frequency current fed to the drum 83 and from this drum to the flexible conveyor 8|, also of conducting material, is not conducted to the shaft 83b. The shaft 03b is provided with a pulley 83c or other suitable driving element coupled to the motor 39 shown in Fig. 1.

Fig. 8 is a top view of the high frequency electrode F, illustrating a modified form of this apparatus employing a thermal relay consisting of a thermally responsive bi-metallic element IOI for closing the contacts I03 and I04. of the contactor He in place of the contactor H shown in Fig. 1. The bi-metallic element IN is anchored to the base of the thermal switch at one end by the bolt I02 and the other endcarrying the contact I04 is movable toward the contact I03 which is fastened to the switch base also. The switch unit is placed partially in the high frequency electric field existing in the region surrounding the electrode F and the adjacent parts of the conveyor 8I so that the bi-metallic element Illl is heated by the high frequency electric currents set up therein and caused to expand, that is, the contact I04 is caused to gradually move up to and engage contact I03 because the strips making up the bi-metallic member IOI are of different materials and have different thermal coefficients of expansion. The time interval required for this expansion may be adjusted as by properly positioning this switch in the field so that this time interval will correspond to the time required to pop the corn in the electric field.

The contacts I03 and I04 are connected to the terminals 31a and 36a respectively and these correspond to the terminals 3! and 36 respectively of Fig. 1 so that it will be apparent that the switch Ha may be used in place of the switch H of Fig. 1.

Fig. 9 is a detail side view of the high frequency electrode F, the electrode support G and the contactor H. The electrode F is a thin sheet of copper encased in insulation I05 of Bakelite or the like to give it mechanical strength and to insulate it and to reduce corona losses from the laths 8Ia attached to the conveyor 8I.

sharp edges and corners. This electrode is supported by the metal tube G when a fresh bag of corn 84 is pushed out of the bin or reservoir 85 by the conveyor BI and one of the transverse As the corn pops through the application of the high frequency field thereto, as more fully explained in the description of the operation of this invention, the electrode F is raised and the tubular element G slides up through the insulation support I03. The tubular element G raises the insulation button shaped member II2, which is fastened to the end of the element G and limits the downward movement of the element G, upward, carrying the contact III of the contactor H fastened to the button I I2 upward also, into engagement with the contact IIO of the contactor H. This condition of contact between the contacts H0 and I II is achieved when the com 84 is fully popped and expanded. The gap between the contacts H0 and III may be changed either increased or decreased by the adjusting knob I08 Which is employed for rotating the threaded member supporting the contact I I0 in the thread- 7 ed metallic support I91. This support is fastened to the insulation bracket I09 which isattached' to the insulator I06.

- .The operation of this invention will now be described. As was previously stated, when the connector plug 10 is connected to a suitable power circuit and the switch II is manually closed the primary of the filament heating transformer 60 (shown in Fig. 2) is energized and the filaments or cathodes of the'electric discharge devices or tubes SI and 62 are heated to electron-emissive temperature. The winding 50 of the electromagnetic shutter is energized by the current flowing through the primary of the transformer 60 and the coin diverting shutter 52 is lifted by the magnetic armature 5| of the winding 50, out of the coin slot 80 so that a coin 9| dropping through the coin slot may move unobstructed down said coin slot and engage the resilient-member A, depressing this member downwards sufficiently to close the contacts 32-33 of the contactor B. Closing the contactor B energizes the electromagnetic lock C which holds the resilient member A in depressed position. The current flowing through the winding C also flows through the conductor 29, the winding D and the contactor K, the contacts-l9 and 2B of which are closed, completing thexcircuit to the conductor i2. Energizing the Winding D functions to close the contacts. E and this connects the primary of the transformer 63 (Fig. 2) to the power circuit lines [2 and I3, thus energizing the electric discharge devices 6! and 62 so as to cause these devices to generate high frequency electrical oscillations, the frequency of said oscillations being determined by the electrical tuning of the tank circuit 63. This electrical tuning may be varied or controlled by adjusting either the capacity or the inductance or both of this tank circuit, and for optimum cornpopping results this frequency should be adjusted somewhere in the neighborhood between 30 and 100 megacycles per second. Of course, other frequencies may be selected with less efficiency. The high frequency currents are fed through the coupling condensers II and i2 and conductors l5 and '16 to the popcorn conveyor 8i and the electrode F. This conveyor 8! may be made of woven copper wire in the form of a copper screen. The conveyor is an endless belt supported bya pair of rotatable drums 32 and 83, the drum'83 being in the form of a metallic cylindersuitable for conducting the high frequency current, fed to it by thebrush Ti, to the electrically conducting conveyor belt 8i. When high frequency current is fed to the conducting belt 8i and the electrode F from the oscillation generator is by means of the conductors l5 and 16, respectively, the popcorn inside of the bag 84, resting on the conveyor 8i directly beneath the electrode F, is subjected to the high frequency current and is popped. This popping causes the bag 84 to expand considerably and raise the electrode F with the result that the contacts H0 and I (Fig. 9) of the contactor H engage each other and close the circuit to the solenoid I. When the solenoid I is energized, it functions toopen the circuit between the contacts [9 and 20 of the contactor K and at thesame time closes the circuit of the mercury switch J since this mercury switch is mounted upon the pivoted armature 86 associated with the solenoid I, shown in Figs. 1 and 3. Closing the circuit of the mercury switchJ operates to energize the motor 39 from the power circuit and at the same time the contacts [9 and 20 are opened, thus deenergiz-' ing the winding of the relay D. The contacts E of the relay D are opened and the anode circuit of the oscillation generator tubes BI and B2 is deenergized. -When the motor 39 is energized, it functions to move the conveyor 8! a sufiicient distance so that the bag of popped corn is dumped from the conveyor over the drum 83 into a suitable chute from which the customer that inserted the coin 9! into the coin slot 80, may extract the popped corn. When the bag of popped corn is dumped over the drum 83, it engages the panshaped lever 92, shown in detail in Figs. 3a and 3b, which is associated with the pivot 93 of the mercury switch J and contactor K. The bag of popped corn thus opens this mercury switch and closes the contactor K so that the circuit of the motor 39 is de-energized. At the same time as the bag of popped cornwas dumped from the conveyor by the operation of the motor 39, an-

other bag of corn was moved into position underneath the suspended electrode F, from the reservoir 85.

The resetting of'the contactor K to its closed position by the bag of popped corn dumped from the conveyor conditioned this apparatus for popping the next bag of corn. It will be observed that when the circuit of the contactor K was opened by energizing the solenoid I through the closing of the contactor H, the solenoid D and the solenoid C were both de-energized so that the anode circuit, of the high frequency generator tubes 6| and 62 was de-energized and the coin actuated resilient member A was released to its normal position. r 9

Furthermore when the apparatus is initially loaded with bags of popcorn to be popped the motor 39 may be connected to the power circuit with the manual switch I20 which is arranged to short the mercury switch J, and the motor run'until a bag of com 84 is in position under the high frequency electrode J. After this operation the switch I20 is opened.

In Figure 10 is illustrated a partially cutaway view of a cabinet I50 adapted to be employed for this apparatus. This cabinet is provided with a conventional coin chute which has a mouth opening on the exterior of the cabinet and which extends into the interior. This coin chute is shown in more detail in Figures 1 and 4. Below the coin chute is the opening for egress of the popped corn and this is arranged so that the bags of popped corn slide down the lower panel there-: of after being dumped off of the conveyor 8| upon the switch tripping member 92 which is directly above the bottom of'the egress opening. An embodiment of this invention has been set forth in detail in the foregoing specification and the attached drawing, however I do not desire to be limited to the details set forth except insofar as they are defined by the following claims.

I claim: 7 I. In apparatus of the class described, the com bination of a high frequency current generator, spaced-apart electrode means connected to said generator for treating material to be processed with high frequency current and positioned therebetween, check actuated switch means for controlling the energization of said high frequency current generator for processing said material, switch means actuated by the material being processed after said material has been processed to the desired degree, and means controlled by said last mentioned switch means for discharging said material after processing.

2. In apparatus of the class described the combination of a high frequency current generator for-generating :a high frequency field, a conveyor for carrying material to be processed with high frequencycurrent into said high frequency field, means for moving said conveyor, control means for controlling the energization of said high frequency current generator for processing said material, said control means including a switch adapted to be closed by the expansion of the said material when said material has been processed to the desired degree to automatically de-energize selected circuits of said generator.

3. In apparatus ofv the class described the combination of a high frequency current generator for generating a high frequency field, a conveyor for carrying material to be processed with high frequency current into said high frequency field, means for moving said conveyor, control means for controlling the energization of said high freveyor, and switch means automatically actuated when said material is processed to the desired degree to .de-energize selected circuits of said generator.

4. In apparatus of the class'described the combination 0152, high frequency current generator for generating a high frequency field, means for positioning material to be processed with high frequency current in said high frequency field, control means for controlling the energization of said high frequency current generator for processing said material, said control means including aswitch adapted to be closed by the expansion of the said material when said material'has been processed to the desired degree, connections for energizing said first mentioned means when said switch is closed to move said processed material out of said high frequency field, and switch means automatically actuated when said material is processed to the desired degree for de-energizing selected circuits of said generator.

5. In apparatus of the class described the combination of a high frequency current generator for generating a high frequency field, a conveyor for positioning popcorn to be popped in said high frequency field, a motor for driving said conveyor, control means for controlling the energization of said high frequency current generator for processing said popcorn until said popcorn has been popped, and switch means automatically actuated by the expansion of said popped corn for connecting said motor to a source of current supply whereby said popped corn is moved out of said high frequency field,

6. In apparatus of the class described the combination of a high frequency current generator for generating a high frequency field, a conveyor for carrying a bag of corn to be popped into said high frequency field, a motor'for driving said conveyor, control means for controlling the energization of said high frequency current generator for processing said corn, and switch means automatically actuated by the expansion of the poped corn in said bag, connections between said switch, said motor and a source of current supply for energizing said motor when said switch is closed whereby said bag of popped corn is moved out of said high frequency field and a bag of unpopped corn is moved into position for the next popping cycle.

7. In apparatus of the class described the combination of a check controlled switch, a high frequency current generator for generating a high frequency field, means controlled by said switch for connecting selected circuits of said generator to a source of current supply, means for moving material to be processed with high frequency current into said high frequency field, control means for holding said check controlled switch closed and for controlling the energization of said high frequency current generator for processing said material, additional control means including a switch adapted to be closed when said material has been processed to the desired degree and connections to said additional control means for disabling said first mentioned control means when said additional control means is actuated.

8. In apparatus of the class described the combination of a check controlled switch, a high frequency current generator for generating a high frequency field, means controlled by said switch for connecting selected circuits of said generator to a source of current supply, means for moving material to be processed with high frequency current into said high frequency field, control means for holding said check controlled switch closed and for controlling the energization of said high frequency current generator for processing said material, additional control means including a switch adapted to be actuated when said material has been processed to the desired degree, connections to said additional control means for disabling said first mentioned control means when said additional control means is actuated and means for adjusting said last mentioned switch to control the degree of processing of said material.

9. In apparatus of the class described the combination ofa check controlled switch, a high frequency current generator for generating a high frequency field, means controlled by said switch for connecting selected circuits of said generator to a source of current supply, means for moving material to be processed with high frequency current into said high frequency field, control means for holding said check controlled switch closed and for controlling the energization of said high frequency current generator for processing said material, additional control means including a switch adapted to be actuated by the expansion of said material being processed, connections to said additional control means for disabling said first mentioned control means when said additional control means is actuated and means for adjusting said last mentioned switch to control the degree of processing of said material.

10. In apparatus of the class described the combination of a check controlled switch, electromagnetic means for locking said switch in closed position, a high frequency current generator for generating a high frequency field, means controlled by said switch for connecting selected circuits of said generator to a source of current supply, means for holding material to be processed with high frequency current in said high frequency field, control means responsive to the processing of said material for controlling the energization of said high frequency current generator, said control means being connected to de-energized selected circuits of said generator and unlock said check controlled switch when said material has been processed to the desired degree, means controlled by said control means for moving said processed material out of said high frequency field, and means for de-energizing said last mentioned means when said processed material is moved out of said high frequency field.

11. In apparatus of the class described the combination of a check controlled switch, eleccontrolled by said switch for connecting selected circuits of said generator to a source of current supply, means for holding material to be processed with high frequency current in said high frequency field, control means responsive to the processing of said material for controlling 'the energization of said high frequency current generator, said control means being connected to de-energized selected circuits of said generator and unlock said check controlled switch when said inaterial'has been processed to the desired degree, means 'controlled by said control means 9 for moving said processed material out of said high freouency field, and a switch for de-energizing said last mentioned means when said processed material is moved out of said high frequency field. 6

12. In apparatus of the class described the combination of a check controlled switch, electro= ma netic means for locking said switch in closed position, a high freouency current generator for generating a high frequency field, means controlled by said switch for connecting selected circuits of said generator to a source of current supply. means for holding material to be processed with high freuuencv current in said high frequency field, control means including a switch responsive to the processing of said material for controlling the energization of said high frequency current generator, said control means being conected to de-energized selected circuits of said generator and unlock said check controlled switch when said-material has" been processedrto the desired degree. means controlled by said control means for moving said processed material mentioned switch to control the degree of processing of said material.

EDWARD L. SCHIAVONE.

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